14/10/2024
Chapter 1 of Class 10 Maths is typically *"Real Numbers"*. Here are some Multiple Choice Questions (MCQs) and Assertion-Reason questions based on this chapter.
# # # **MCQs:**
1. **The HCF of two numbers is 6 and their LCM is 72. If one number is 24, what is the other number?**
a) 12
b) 18
c) 36
d) 48
**Answer:** b) 18
2. **The decimal expansion of the rational number \(\frac{14587}{1250}\) will terminate after:**
a) 2 decimal places
b) 3 decimal places
c) 4 decimal places
d) 5 decimal places
**Answer:** c) 4 decimal places
3. **Which of the following is an irrational number?**
a) \(\frac{22}{7}\)
b) \(0.333\ldots\)
c) \(\sqrt{2}\)
d) 1.41414141…
**Answer:** c) \(\sqrt{2}\)
4. **If two positive integers \(a\) and \(b\) are expressed as \(a = 2^2 \times 3 \times 5\) and \(b = 2 \times 3^2 \times 7\), then HCF \((a, b)\) is:**
a) 42
b) 30
c) 60
d) 6
**Answer:** d) 6
5. **The least number that is divisible by all the numbers between 1 and 10 (both inclusive) is:**
a) 504
b) 1000
c) 2520
d) 840
**Answer:** c) 2520
---
# # # **Assertion-Reason Questions:**
**Assertion (A):** The sum of a rational and an irrational number is always irrational.
**Reason (R):** Irrational numbers have non-terminating, non-repeating decimal expansions.
a) Both A and R are true, and R is the correct explanation of A.
b) Both A and R are true, but R is not the correct explanation of A.
c) A is true, but R is false.
d) A is false, but R is true.
**Answer:** a) Both A and R are true, and R is the correct explanation of A.
---
**Assertion (A):** Every composite number can be factorized as a product of primes.
**Reason (R):** Fundamental Theorem of Arithmetic states that every composite number can be expressed as a product of primes in a unique way (apart from the order of the prime factors).
a) Both A and R are true, and R is the correct explanation of A.
b) Both A and R are true, but R is not the correct explanation of A.
c) A is true, but R is false.
d) A is false, but R is true.
**Answer:** a) Both A and R are true, and R is the correct explanation of A.
---
**Assertion (A):** The LCM of two co-prime numbers is always their product.
**Reason (R):** Co-prime numbers are those that do not have any common factors other than 1.
a) Both A and R are true, and R is the correct explanation of A.
b) Both A and R are true, but R is not the correct explanation of A.
c) A is true, but R is false.
d) A is false, but R is true.
**Answer:** a) Both A and R are true, and R is the correct explanation of A.
---
**Assertion (A):** If \(p\) is a prime number, then \(\sqrt{p}\) is irrational.
**Reason (R):** A number is said to be irrational if it cannot be expressed in the form of \(\frac{p}{q}\), where \(p\) and \(q\) are integers and \(q \neq 0\).
a) Both A and R are true, and R is the correct explanation of A.
b) Both A and R are true, but R is not the correct explanation of A.
c) A is true, but R is false.
d) A is false, but R is true.
**Answer:** a) Both A and R are true, and R is the correct explanation of A.
These questions will help students get a better understanding of the concepts from Chapter 1 on Real Numbers.